ipa: rkisp1: agc: Store per-frame information in frame context

Rework the algorithm's usage of the active state to store the value of
controls for the last queued request in the queueRequest() function, and
store a copy of the values in the corresponding frame context.

The frame context is used in the prepare() function to populate the ISP
parameters with values corresponding to the right frame.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

2 files changed, 21 insertions, 9 deletions

diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
index 10958a7e..04062a36 100644
--- a/src/ipa/rkisp1/algorithms/agc.cpp
+++ b/src/ipa/rkisp1/algorithms/agc.cpp
@@ -144,17 +144,19 @@ utils::Duration Agc::filterExposure(utils::Duration exposureValue)
 /**
  * \brief Estimate the new exposure and gain values
  * \param[inout] context The shared IPA Context
+ * \param[in] frameContext The FrameContext for this frame
  * \param[in] yGain The gain calculated on the current brightness level
  * \param[in] iqMeanGain The gain calculated based on the relative luminance target
  */
-void Agc::computeExposure(IPAContext &context, double yGain, double iqMeanGain)
+void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
+			  double yGain, double iqMeanGain)
 {
 	IPASessionConfiguration &configuration = context.configuration;
 	IPAActiveState &activeState = context.activeState;
 
 	/* Get the effective exposure and gain applied on the sensor. */
-	uint32_t exposure = activeState.sensor.exposure;
-	double analogueGain = activeState.sensor.gain;
+	uint32_t exposure = frameContext.sensor.exposure;
+	double analogueGain = frameContext.sensor.gain;
 
 	/* Use the highest of the two gain estimates. */
 	double evGain = std::max(yGain, iqMeanGain);
@@ -286,9 +288,16 @@ double Agc::measureBrightness(const rkisp1_cif_isp_hist_stat *hist) const
  * new exposure and gain for the scene.
  */
 void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
-		  [[maybe_unused]] IPAFrameContext &frameContext,
-		  const rkisp1_stat_buffer *stats)
+		  IPAFrameContext &frameContext, const rkisp1_stat_buffer *stats)
 {
+	/*
+	 * \todo Verify that the exposure and gain applied by the sensor for
+	 * this frame match what has been requested. This isn't a hard
+	 * requirement for stability of the AGC (the guarantee we need in
+	 * automatic mode is a perfect match between the frame and the values
+	 * we receive), but is important in manual mode.
+	 */
+
 	const rkisp1_cif_isp_stat *params = &stats->params;
 	ASSERT(stats->meas_type & RKISP1_CIF_ISP_STAT_AUTOEXP);
 
@@ -320,7 +329,7 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
 			break;
 	}
 
-	computeExposure(context, yGain, iqMeanGain);
+	computeExposure(context, frameContext, yGain, iqMeanGain);
 	frameCount_++;
 }
 
@@ -328,9 +337,11 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
  * \copydoc libcamera::ipa::Algorithm::prepare
  */
 void Agc::prepare(IPAContext &context, const uint32_t frame,
-		  [[maybe_unused]] IPAFrameContext &frameContext,
-		  rkisp1_params_cfg *params)
+		  IPAFrameContext &frameContext, rkisp1_params_cfg *params)
 {
+	frameContext.agc.exposure = context.activeState.agc.exposure;
+	frameContext.agc.gain = context.activeState.agc.gain;
+
 	if (frame > 0)
 		return;
 
diff --git a/src/ipa/rkisp1/algorithms/agc.h b/src/ipa/rkisp1/algorithms/agc.h
index f115ba2e..9ad5c32f 100644
--- a/src/ipa/rkisp1/algorithms/agc.h
+++ b/src/ipa/rkisp1/algorithms/agc.h
@@ -34,7 +34,8 @@ public:
 		     const rkisp1_stat_buffer *stats) override;
 
 private:
-	void computeExposure(IPAContext &Context, double yGain, double iqMeanGain);
+	void computeExposure(IPAContext &Context, IPAFrameContext &frameContext,
+			     double yGain, double iqMeanGain);
 	utils::Duration filterExposure(utils::Duration exposureValue);
 	double estimateLuminance(const rkisp1_cif_isp_ae_stat *ae, double gain);
 	double measureBrightness(const rkisp1_cif_isp_hist_stat *hist) const;